When time and space are heated, an expanding universe can emerge, without requiring anything like a “Big Bang”. This phase transition between empty space and an expanding universe containing mass has now been mathematically described by a research team at the Vienna University of Technology, together with colleagues from Harvard, the MIT and Edinburgh. The idea behind this result is a remarkable connection between quantum field theory and Einstein’s theory of relativity.

Everybody knows of the transitions between liquid, solid and gaseous phases. But also time and space can undergo a phase transition, as the physicists Steven Hawking and Don Page pointed out in 1983. They calculated that empty space can turn into a black hole at a specific temperature.

Can a similar process create a whole expanding universe such as ours? Daniel Grumiller from the Vienna University of Technology looked into this, together with colleagues from the USA and Great Britain. Their calculations show that there is indeed a critical temperature at which an empty, flat spacetime turns into an expanding universe with mass. “The empty spacetime starts to boil, little bubbles form, one of which expands and eventually takes up all of spacetime”, explains Grumiller.

For this to be possible, the universe has to rotate – so the recipe for creating the universe is “apply heat and stir”. However, the required rotation can be arbitrarily small. In a first step, a spacetime with only two spatial dimensions was considered. “But there is no reason why the same should not be true for a universe with three spatial dimensions”, says Grumiller.

Our own universe does not seem to have come into existence this way. The phase-transition model is not meant to replace the theory of the Big Bang. “Today, cosmologists know a lot about the early universe – we are not challenging their findings. But we are interested in the question, which phase transitions are possible for time and space and how the mathematical structure of spacetime can be described” says Grumiller.

The new theory is the logical next step after the so called “AdS-CFT correspondence”, a conjecture put forward in 1997, which has strongly influenced fundamental physics research ever since. It describes a peculiar connection between theories of gravity and quantum field theories – two areas which, at first glance, do not have much in common. In certain limiting cases, according to AdS-CFT correspondence, statements from quantum field theories can be translated into statements concerning gravitational theories and vice versa. This is almost as surprising as the idea of making statements about a stone falling to the ground by actually calculating the temperature of a hot gas. Two completely different areas are being connected – but it works.

In this kind of correspondence, the quantum field theory is always described in one fewer dimension than the gravitational theory. This is called “holographic principle”. Similar to a two dimensional hologram which can depict a three dimensional object, a quantum field theory with two spatial dimensions can describe a physical situation in three spatial dimensions.

To do this, the gravitational calculations usually have to be done in an exotic kind of geometry – in so-called “Anti-de-Sitter-spaces”, which are quite different from the flat geometry we are used to. However, it has been suspected for a while, that there may be a similar version of the “holographic principle” for flat spacetimes. But for a long time there haven’t been any models showing this.

Last year, Daniel Grumiller and colleagues established such a model (in two spatial dimensions, for simplicity). This led to the current question; phase transitions in quantum field theories are well known. But for symmetry reasons this would mean that gravitational theories should exhibit phase transitions too.

“At first, this was a mystery for us”, says Daniel Grumiller. “This would mean a phase transition between an empty spacetime and an expanding universe. To us, this sounded extremely implausible.” But the calculations showed exactly that. “We are only beginning to understand these remarkable correspondence relations”, says Daniel Grumiller. Which new ideas about our own universe can be derived from this, is hard to say – only spacetime will tell.

The image at the top of the page illustrates the cosmic distance ladder astronomers use to measure the expansion rate of the universe, as well as its size and age. The cosmic distance ladder, symbolically shown here in this artist's concept, is a series of stars and other objects within galaxies that have known distances.

The hubris that this theory is based upon is mind-boggling. Here we are, a privative tribe of hairy little apes who, less than a hundred thousand years ago, climbed down from the tops of the trees, stood upright and looked over the tops of the grass.

Just think about how primitive we are... down here on the first couple rungs of our evolutionary ladder. Consider this... the first sharks (as we know them) appeared in the early Devonian period about 400 million years ago. It took them that long to evolve into the perfect hunting and killing machines they are today.

Yet here we are a species of far from perfect critters, who because we've traveled down a different path, have the audacity to proclaim our LOCAL collection of galaxies is indeed the INFINITE universe. This is kinda like postulating that the earth is the center of the universe and all the stars, etc. revolve around us.

Unfortunately Homo Saipan's awareness is limited by its flawed ability to perceive beyond its painfully limited horizons. Our specie's perceptions are clouded by imperfections in our
ability to separate the apparent from the real.

Whether or not these theories or calculations turn out to be true, I still think it in good exercise that we consider them. Even the most outlandish ideas get people at least get people to talk about if it is correct or not, which is all scientists are trying to do. I'm sure the conversion rate of hypothesis to theory is spectacularly low, but the success of correctness comes from knowing what isn't.

@Oligonicella @Kotys virtual particles produce random energy fluctuations and introduce heat into the vacuum. If you don't "believe" in virtual particles...talk to Casimir...

The fact is, that given a time t and any event E with finite probability p will have p approach 1 as t approaches infinity. In other words, damn near certain. That's why you and I are here right now...it was always a certainty and your visions of causality and what is and isn't possible is flawed.

I'm aware of virtual particles, don't condescend. We've yet to understand exactly what time or space is, so claiming they can go through phases is somewhat nebulous. Claiming that a cause has a probability and therefore is what happened isn't much of a leg, especially if it presumes a philosophical starting point instead of a demonstrable one.

Einstein wrote, “According to the general theory of relativity, the geometrical properties of space are not independent, but they are determined by matter.”

Big Bang and inflation models are two very different approaches to the beginning of our Universe.
According to the BB theory, our Universe sprang into existence as "singularity" (matter is actually squished into infinite density, all Universe was a single point) - explosive beginning . Prior to the singularity, nothing existed, no space, time, matter, or energy - nothing.
According to the inflation model the Universe doesn't start from nothing, but from a sort of "primordial" energy (and info, my addition). The early Universe came through the stage of inflation, exponentially rapid expansion in a kind of unstable vacuum-like state, with large energy density, but no matter in any form. Vacuum-like state in inflationary theory usually is associated with a scalar field, often called "inflation field." Universe pops into existence huge, but not explosively.
Inflation models suppose cyclic evolution of the universes, Big Bang - accidental one-time event.
Some researchers are creating a fancy mix of BB and inflation cosmology, in order to save the big bang hypothesis. The big bang idea is already part of the legion of failed theories which constitute the painful development of humans science.
The term inflation is a bit misleading because it involves nothing like an inflating balloon, but rather an instantaneous ripple in the scalar-field-like, which is losing energy, giving it up in the form of vibrating strings/particles. Mass and energy are interchangeable: E=mc2. The Universe doesn’t become bigger and big-ger like an inflating balloon. It just pops, enormously huge, into existence and then expands.
The Universe starts only as matter, there is still no spacetime.
With the matter comes gravitation, with gravitation comes the curvature of space; still no time (at least in the form that we know it). - excerpt from book The Hidden Alpha by Alexander Popoff.

Please. Space is defined by matter, time is defined by movement. If you have matter you have both space and time. Space because matter has dimension, time because matter moves.
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You are almost right. Universe starts from specific form of vibrating energy that turns into matter, but in the moment of the transition there is still no spacetime. This moment is extremely short, but it exists. The moment of transition here is very important in order to understand the process.

The headline does reflect the content of the article. I expect false, attention getting, headlines from the lay media but not from a supposed scientific journal. More accurately it should say "A Universe Without a Big Bang", rather than, "The Universe...."

Per the body of the article, "Our own universe does not seem to have come into existence this way. The phase-transition model is not meant to replace the theory of the Big Bang."

If energy is neither created nor destroyed, i.e. it is eternal, infinite, then such energy can manifest itself in various forms, and our "Universe" is one such manifestation-perhaps undergoing a phase change from pure energy to singularity to an expansion.

Consider an hourglass, and all the sand on one side of the hourglass as infinite energy and when it's turned, the bit that starts pouring on the other side is what we've labelled as the "Universe". Although one might argue that all the sand should be labelled as the Universe, not just the bit that we can observe. The whole is the sum of the parts.

Please correct me if I'm wrong but isn't,"calculated that empty space can turn into a black hole at a specific temperature,'' a misnomer? To have any temperature at any level, isn't it a prerequisite that matter and/or energy must be present, therefore you would not able to experience 'empty space' in such conditions?

Regarding the Big Bang theory. A "big bang" would be an uncontrolled explosion, totally chaotic without order of any kind. But that's not what we observe in the universe. In the Milky Way we observe order of the highest kind. There is order in the Solar System, there is order in the star groups that compose the Milky Way. There is order in all the visible galaxies, groups of galaxies and super groups of galaxies. All in motion and all in harmony.

There is order also on the atomic level as demonstrated in the periodic table. The universe is governed by law. The laws of physics, the laws of atomic and subatomic structures, the laws of genetics etc. The weak force, the strong force, gravity and electromagnetism. So how did all this order and these natural laws come about? It was caused. But by Something or Someone? Herein lies the impasse between the theists and the atheists.

is Mr D. Steeves an idiot or a creationist? perfect order in the universe? what about the blue and red shifted galaxies, which will eventuallycollide, an ever expanding universe? i think not. but a series of universes spewed out by the collision of two massive black holes. ad infinitum